Mill



May 18, 1948. L. s. vlFuzl-:RSEN A MILL Filed Feb. 9, 1946 l 2 sheets-sheet 1 fwn TOR

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ATTORNEYS l May 18, 1948. s PETERSEN 2,441,901

MILL

' Filed Feb. 9, 1946 2 Sheets-Sheet 2 ,f @f f6' ATTORNEYS Patented May 18 1948 f U-NITED STATES `PATENT *OFFICE Y g r@MILL n A. t

F. L. Smidth & Co., New York, ration of New Jersey Application February 9, 1946, Serial No. 646,584

This invention relates to apparatus of the type that includes a generally cylindrical shell mounted for rotation on its longitudinal axis, examples of such apparatus being ball mills, rotary kilns, certain forms of dryer, etc. More particularly, the invention is concerned with a novel apparatus ofthe kind mentioned which is superior to prior equipment with respect to the means by which the shell is supported and rotated. While the new apparatus may take various forms, as indicated above, the invention may be embodied to especial advantage in ball -mills and its application to that field will, accordingly, be illustrated and described in detail for purposes of explanation. Y

Ball mills consist essentially of a generally cylindrical shell or drum mounted with its longitudinal axis horizontal and supported for rotation on that axis. The shell is closed at its ends and is provided with an inlet at one end through which material to be ground may be introduced by appropriate means, such as Va rotary scoop within a casing, and with an outlet at the other end through which the ground material is discharged.

2 Claims. (Cl. 711-421) In my co-pending application, Serial No.

505,729, filed October 11, 1943, now Patent No. 2,396,057, I have disclosed an apparatus, such as a ball mill, which includes a cylindrical shell mounted for rotation with its axis horizontal and encircled by a ring lying about midway between its ends. In the construction, which is preferred when the mill is of great weight, the ring is formed with a pair of peripheralgear sections and a smooth surfaced peripheral section lying between the gear sections and serving as a tire. The mill is supported by means, such asr slide shoes, which engage the tire, and it is kept fromtilting in any suitable manner, as by means Aof a shaft secured to the mill at the inlet end and mounted for rotation in a bearing. The mill is rotated by a drive shaft which has pinions engaging the respective gear sections and the lshaft is supported for rotation in fixed bearings, although the bearings maybe of the self-aligning type.

The mill shown in the co-pending application` oiers advantages over prior mills rotated by a single master gear driven by a drive pinion, for the following reasons.,v When a single master gear and pinion areused, they must' be very strong, because of the large amount of power transmitted through their teeth, and the cost of such a gear is high and its manufacture is diflicult. In the mill of the co-pending application, in which the ring encircling the shell is provid with two gear sections driven by separate pinions, only half the power required for driving the mill istransmitted through the teeth of each pinion and its gear vsection and the cost of such gear sections is substantially less than that of a Vsingle master gear. However, my prior mill requires the use of an anti-tilting bearing, and also that section of the drive shaft carrying the drive pinions must be supported by a bearing, so that the shaft can not adjust itself to the vextent desirable to insure proper tooth pressure on both drive pinions and their gear sections at all times.r

The present invention is directed to the kprovision of an apparatus, such as a ball mill, which includes a cylindrical shell provided with means which support the shell between its ends in such fashion that no anti-tilting bearing is required. In addition, the shell of ythe new apparatus is driven by means of a single master gear, but power is transmitted to the gear by a pair of idlerpinions, so that the gear need be only half as strong as would be necessary, if a single drive pinion wereused. 1

For a better understanding of the invention, reference may be made to the accompanying drawings, in which:

lFig, l is aA view of `the new apparatus in side elevation, vwith the mounting means shown in vertical section; f f- Fig. 2` is a sectional view on the line 2- 2 of Fig. 1; and Y e Y.,

Figs. 3 and 4 are sectional Views on the lines 3 3 and 4 4, respectively, of Fig.v 2.

The new apparatus is illustrated in theform of a'ball mill, whichvco'mpris'es a cylindrical shell I0 having an inlet opening llat .onelend'and an outlet opening l2 yat, the other.A The shell is of conventional construction and, midway betweenits ends,.a series of blocks I3 aresecured -to its outer surface by welding and extending both radially,Y and. axially of the shell. Arcuate wedge membersfllla', Mb are mounted in pairs against the outer surfaces of a plurality ofy adjacent blocks near their ends, and, -nl the construction shown, each wedge member bears against apair of blocks.` The wedge members of each pairk have inwardly convergent topsurfaces and a ring l5 having inwardly'conver'gent inner surfaces rests on top of the pairs of wedge members |4a,l4b. The ring has an. inner' peripheral flange I6 formed with openings'therethrough and the wedge members of each pair are secured together by bolts I1, which pass through the Wedge members and through the flange I6 of the ring. When the bolts are drawn up, the wedge members act against the A Pairs of slide shoes 2D mounted on supports 2-l` on a foundation 22 engage the respective tie sections I and the shoes constitute the sole sup' port for the shell. A pair of,.shafts .23 are.. mounted in self-aligning bearings'zlt'supported on the foundation and an idlerpinion"Zilinountedv on each shaft meshes with the gear section IB Y on ring l5. Y

The idler pinions are driven by a drive 4.pinion 26 on the end section.-2'la of a drive shaftV 2T driven by a motor.28. 'Adjacent the motort,he

.shaft 121 isfrnoliintf-id'` innaixed' yl'l'earin'gjjZS and, 'b eyond the" bearing toward its free end, theV shaft is provided' with-jamembra'ne coupling'generally "designated 30",.fwhich' connects it to' an intermediate sectionzlb. The"couplingcomprises"a hub '3 l' on" the Vmain 'partof 4shaft'l, anda dished circular'plate 32"atta'ched'to"the'hub: The outer edge'ofithe plate -issecured'toY aplurality of thin Y'flexibleplates"Z13 which areboltedto -a hub *34 mounted ion JoneA end on' the intermediate shaft section "21 b. 1 'The otheienidlV of'V4 the intermediate shaft sectiontisattachedby`a second; membrane coupling.J 35lto. 'one en'dofj` the" kenel `section'-2'la 'of't'he shaft; VlVith' suc'h amounting, the' shaft directions without; inclination' Vof' its "axis, 'and this' insures 'thatl the drive, pinion. 2 6 will.` ndits 'are enclosed within a'casin'gwhich is supported in diameter and weighs one hundred forty thousand pounds, a load of twenty thousand pounds must be applied at one end of the shell before tilting starts.

Since the mill is driven fromvthe drive shaft through the two idler pinions, those pinions and ,the` teethlof ,gear` sectionvk i.8ineedb.e,or1ly half as `strong'asvvouldbe necessary, if the Ydrive pinion acted directly on the gear section. Also, since the drive pinion is mounted between the idler pinions and the shaft section carrying the drive pinion is free to float, the action of the two idler ,pinions on the drive pinion keeps the latter in positionftoinsureffproper tooth pressure at all timesVv A- Since the new mill does not require any antit'ilti-ngifbearn-1g;the construction is simplified and the.n cost. reduced. A further reduction in cost results from the use of a master gear section, whichis driven through* two idler pinions instead lof directlyfrom a single pinion on the drive shaft.

-11 Apparatus `of 'the' type described, vwhich Y comprisesv a generally/"cylindrical shell, a meinber encircling landgsecured to the shellg-the'member' having a pair-of srnoothsurfaced tire sections and a gear'section between thel tire sections, a

"foundation, sets 'of slide shoesfmountedon the foundation -and engaging theA respective tire sections,A the slicesV forming l the-sole support for Ythe shell in its rotationya pairy ofr shafts beneath Athe shell, Aan idierj pinion on each-V shat; the; teeth of the `pin-ionsrneshingwith-thoserof thegear seconthe foundation 22 and has openings-,inqits Y oppositewal'ls throughwhichtheshell extends.

Sealing"means `-2V! mountediavthej edges of the openingsengage the end surfaescf the'ring and 'preventthe accessofidustto the'gearteeth; 'The `casing"hasf"an"opening through which the-"shaft .section 21a extends, and a res'ilientmsealfwis "mountedon the casingwall to'encircle the`- shaft section. 21a. at the opening The sealiis' so constructed that itidoesnot' interfere' with the floating .movement-of thefshaftsection. `In lorder4 to vWith the' construction described', the 'slide shoes '120,1'bearing von'thetire sections 'I9 of ringv l5, kgprtrvide'theV sole support for the' -mill and it is not necessary tomake useo'fan'antietilting bear'- ing at eitherend thereof Even though the; distance betweenl the. centers-bf the* Vtires jisrelatively smal'l; the' weightl that must 'be' applied to "oneendofj the mill;tocause'thelatter tobegin to tilt," is much -greater than any' unbalanced load that'is' likely "towoccur'j'in normal operation.

"Thus, with. theslide 'shoebearings' separatedv by a distance .equaltoone-ei'ghth. of the length of a shel1-.whichlis "'fi'fteen; feet long" and` seven feet tion, a drive shaft having an end section -supported,Vr for` floating movement', Aand a pinion-V on said iend section lying between anddriving VVthe idlerpinionsandftheirfshafts.

2. Apparatus 'ofthe Vtype described, which comprises a rgenerally` cylindrical shell, Y a 1 einem vberVv encircling and' securedto the s'hell,fthefmem ber having a lpa-ir ofz smoothsurfaeed 'tire sections anid'f a gearV section? between'- the tire sections,C af foundation, sets of slideshoesfmounted on the foundation and engaging the respective tire sections, the shoes fr )rmingv the-sole support for thevshelly its'L rotation; afpair :of`- shaftsfbenea-th the -'shelL an idler pinion vvon each f shaft, the! teethofi the pinions 1 meshing Withythose of the gear section,Y lav drive shaft T having Yan end sectionsupported' for iioating movement', resilient means' tendingl to raise2 said-1' en'd section, and Va pinion fon* Ysaidend sectionv 'driving the AAidler pinicns'.-and-"theirlshaftsV i n' j'LoUIs v1s. f-PETERSEN.

' REFERENQESGITED Y rfhe following., references Aare off recordzl ini the vfile of this patent:

UNiTED. lSTATES eAfrENrrs Number Y Name I Date 1,055,599 ABall Y 'Mar. 11, 1913 1,157;91sf vAiquist oct. 2e, A1915 1,351,321 i A1quist7 Aussi, 1920 `1536g491 i VVVG underoth V V Mayl5,'1925 Y VYi'ioiftniciuPATENTS Number Countryv Date Great Britainv 1----' Aug; 14, 1924 

